Facing tool



Dec. 8, 1964 c. R. PHILLIPS 3, 60,066

FACING TOOL Filed Aug. 3, 1961 ATTORNEY? United States Patent 3,160,056 FACING TUQL (Iiivy R. Phillips, Houston, Tex, assignor to Hudson Engineering Corporation, Houston, Tex. Filed Aug. 3, 1%1, Ser. No. 129,051 3 ,lainis. (Cl. 9tli2) This invention is an improved tool for machining and facing an annular surface about an opening. It is particularly useful in facing a surface to receive a gasket about an opening in a header box of a tube-type heat exchanger, in facing flange fitting, valve seats or other applications in which an annular surface around an opening is to be faced.

Heat exchangers of the type common in the petroleum industry usually are composed of a large number of tubes connected to a header box at each end. The header box ordinarily has an aperture opposite the end of each tube, and the aperture is closed with a plug. The purpose of the removable plug is to permit access to the tubes for cleaning, which is required at frequent intervals. Ordinarily the apertures are threaded; and when the tubes are to be cleaned, the plugs are merely unscrewed from the threaded opening. Cleaning operations are rather severe, and the threads and openings in the header box are often battered or burred sufiiciently during the cleaning process that the plug, when replaced in the openings, does not fit tightly and will leak. It is customary to use flange plugs and to place a gasket between the flange on such plug and a plane surface on the exterior of the header box around the aperture so that tightening the plug against the gasket makes the header leak-proof. However, when the threaded opening has been battered by the cleaning operation, it is often necessary to enlarge the opening, tap in new threads, and use a larger plug to secure a tight fitting closure. When this operation is necessary, it is also necessary to enlarge and reface the surface on the header box surrounding the opening so that gasket may fit properly between the surface of the header box and a flange on the new and larger plug.

ddhhfihh v Patented Dec. 8, 1%64 It is an object of this invention to provide a tool for facing a surface around an aperture with which the facing operation may be performed quickly and easily and a resulting faced surface may be immediately inspected by the operator at any time.

Another object is to provide a tool of this class which is light in weight, simple in construction, cheap to manufacture and maintain and which does not require a highly A number of machines for this use have been developed and are on the market at present. These tools are inherently complex, heavy and expensive to manufacture. In addition, since these tools ordinarily use a drive shaft and a holding shaft with gear arrangements on each, they are quite diflicult to maintain in proper alignment with the surface to be refaced when that surface is perpendicular. The heavy weight of a machine of this sort depending from a shaft run into the hole has a tendency to cause a cutting tool to cut deeper into the surface to be faced immediately below the opening than on the opposite side above the opening. Machines of this type usually require the services of a skilled operator in preventing unevenness of cut on opposite sides of the hole and in adjusting the depth of cut to be made. Some of the machines in common use have no stop at all and depend entirely upon the operators ability to judge the depth of cut that he must make although the cutting face of the. tool is not visible to the operator. Other tools are so heavy that they require a means of support such as an overhead crane to prevent weight of the machine from forcing the cutting tool out of the plane desired in the finished surface. When a supporting means of this type is used, it must be adjusted to give only that degree of support which is required to balance the tool; otherwise, too

much life applied to the tool can cause the cutting face to bite deeper into the surface above the opening than below it.

Thus, it will be seen that the machines of the present type require skilled operators and are rather slow and time consuming in transfer from one aperture to another and in adjustment to face surfaces properly.

skilled operator.

Another object is to provide a tool of this class in which weight of the tool does not tend to cause a surface being faced to heart deeper on one side of the aperture than on the opposite side when the tool is used against a perpendicular surface.

Another object is to provide a tool of this class which does not require lifting or balancing means during the cutting operation.

Still another object is to provide a machine ofthis type in which the depth of cut is positively limited and in which setting for correct depth may be accomplished simply and quickly.

Other objects and advantages will become, apparent to those skilled in the art upon consideration of the following specification, claims and the attached drawings.

In the present invention a very simple, light weight, cheap tool for facing an annular surface about an aperture is provided. This tool enables an unskilled workman to do a first-class job of facing the surface merely by pushing in on the rotating tool and enables him to back thetool up slightly to inspect the surface being faced at any time.

The tool comprises a rigid, tubular bearing having a section adjacent to one end of the bearing fitting tightly into a central aperture through the surface to be faced. In one preferred form, useful in threaded openings, the hearing has a series of external threads on its outer end; that is, the end of the bearing opposite the end first inserted into the aperture. These threads, of course, match the internal threads of the threaded aperture; and a hearing installed in this manner supplies a rigid support for a shaft which is longitudinally movable and rotatable in the bearing. A surface facing member which may be a milling cutter, a grinding wheel or the like is carried by the shaft outside the bearing adjacent to and facing said one end of the bearing in position to be thrust into engagement with the surface to be faced on movement of the shaft further into the bearing and to be withdrawn to permit the operator to inspect the surface being faced by movement of the shaft in the opposite direction A positive stop is provided to prevent the facing element from cutting too deeply into the work, Preferably, this stop comprises an outward facing shoulder on the interior of the bearing and an inward facing shoulder'on the shaft; but other opposed surfaces of the shaft and bearing may be used if desired. For example, the inner end of the bearing might be closed, and that part of the shaft entering the bearing might be of such length that the end of the shaft would contact the end of the hearing at the maximum desired depth; or a shoulder on the shaft may be located to contact the outer end of the bearing.

in one preferred form, the hearing has an outer threaded external portion adapted to fit tightly into a threaded aperture and has a long section extending into the interior of an article to be faced on its outer surface. The elongated form of. the bearing gives great rigidity to the shaft. The preferred facing member is a transverse milling cutter disposed ina transverse slot or opening through the shaft and held firmly in place by a nut screwed upon a threaded shoulder of the shaft.

In the attached drawings, wherein like characters are used throughout to designate like parts:

PEG. 1 is an expioded view of a tool constructed according to the principles of the present invention; and

FIG. 2'is a view of the tool of FIG. 1, partly in section, and illustrating its relationship to a header 'box when used therewith.

In the drawings, the reference numeral S-designates an elongated rigidbearing having heavy. sidewalls 6' having such external dimensions as to be freely, insert'able into aperture 81' The bearing, has a threaded section 7 adjacent its outer end having external'dimensions such as'to fit tightly into an internally. threadd'aperture 8 of a workpiece, illustrated'as headerr box '9. The'bearing 5 is equipped with means for engaging an inserting tool, illustrated'as slots 11, in the'out'e'r endi12 of the hearing. The bearing shown thus may-bescrewed firmly into the threaded "opening 8 by 'useof'a tool having blades engaging slots 11' andwill normally be in'sertedto a depth in' the threaded aperture slightly greate'rth'an'the' depth to which the exterior ofheadenbox 9'is to becut away to form the finished surface. Driving .thebearing to this depth is the preferred method ofattachment'since a small clearance is thus provided betweenthe cutting'face of the surface facing member, illustrated as a' milling cutter 13, andthe outer end ofthe bearing;

Cutter 13 is'carried by shaft outside the bearing in position to'be thrust against the'surtacel' t'to be faced on movement of shaft 10 further into bearing 55 A preferred means for'attaching the cutter'13'to shaft 10 is a threaded shoulder 15 on' shaft 10 having a transverse opening 16 adjacent thereto ofsu'ch'size as to admit the cutter 13'freely and'a-nut 17 screwedupon-shoulder 15 to hold cutter 13 firmly in slot 16;

Shaft 10" has an extension 1% on'the side of shoulder 15 op'posite to thebe'aring whichserves as a'drivin'g shank for attaching to an air motor or other driving means. The bore of bearing 5 has a shoulder 19*opposinga shoulder 20 on shaft 10 and servin'g'as a positive stop to advancement of the shaft intothe bearing and the cutter carriedby the shaft;

It is believed that operation of'the'device is obvious from the above description: When aplughas been removed from threaded opening-8 for cleaning tube 21' and during the cleaning operation, the threads of the opening are damaged so that the'opening must be enlarged and rethreaded with the ensuing necessity for enlarging the gasket-receiving surface 14': The bearing 5 is screwed into the enlarged threaded opening-Shy use of a suitable tool having bladesengaging slots 11; A cutter of required dimension is inserted in slot 16, and the nut 17 is tightened upon the cutter to hold it firmlyin place, and the shaft 10 is inserted-in'bcaring 5;

The chuck of an air motor, portable electric drill or any other driving'meansrequired is attached to the outer extension 18 0f shaft 10L The shaft is rotated, and the operator pushes straightin on the tool. Because of the heavy walls 6'; the bearing 5 is quite rigid and there is no tendency for the cutter 13 to wobble as it rotates with shaft 16. As the leading edge of cutter 13 comes in contact withthe surface to be refaced, it mills away metal to give an annular planar surface'around' the aperture 8 normal to the axis of the aperture. There is no danger of the operator cutting toodeep because, as the cutter works its way into the metal of header box 9 to the desired depth, the shoulders'19' and'Zllon the bearing and shaft, respectively, approach each other until contact is made at the desireddepth of cut. No deeper cuttingis possible, and thus no particular skill is required of the operator; The shaft is then withdrawn from the bearing; the bearing is unscrewed from aperture 8; and a gasketed plug is inserted, thus effectively closing the aperture.

It is obvious that a great many modifications of the device described in detail above may be made without departing from the spirit of the invention. For example, many other types of cutters than the straight milling cutter 13 illustrated may be used. The surface 14 to be faced need not be a planar surface normal to the aperture but may be a sloped or curved surface if desired. A grinding wheel mounted transverselyton shaft 10 may be used if desired, and very fine wheels may be advantageous when the surface is to be highly polished.

The extension 18 of the shaft instead of being round to fit into a chuck may be of any shape desired to fit into any sort of driving means as, for example, be squared to receive a. square socket in'a manually operable handle. The bearing'itself need not be th'readed except when the aperture is a threaded one but may be press fitted into a plain aperture; When the surface to be faced is located upon a raised annulus around-the aperture, the bearing neednot be inserted'for its' full length'into the aperture;

and in this case, a hexagonal or. square head'might be 7 substituted for the slots 11' as a meansfor'in'serting the bearing.

From theforegoing, it willbeseen'that'this invention is one Welladapted to attain allof the ends" and objects hereinabove set forth, together with other advantages which are obvious and 'whichare inherent to the apparatus.

It will be understood that certain features and subcombinations are of'utilityand'may be employed without reference to other features and subcombinations. This is contemplated by and is within-the scope of the claims;

As many possibleembodiments' may be made of the invention without departing from the scope-thereof, it is to be understood that'all matter herein set forth or shown in theaccompanying drawings is to bra-interpreted as'illustrative and not in alimiting sense;

The invention having been described, what'iscl'aimed is:

1. A tool for facing an annular surface around an aperture in a work piece comprising in combination a rigid tubular bearing, including a'first section adjacent to one end of the bearing having external dimensions such as to fit tightly into-an aperture in a work piece and a second elongate section having external'dimensions such as to-be' freely insertable into the aperture; a shaft longitudinally movable in and rotatable in the'bearing, said shattthaving a driving shank outside said one end of the bearing; a surface facing member carried by the shaft between the bearing and shank adjacent'to and facing said one end of'the bearing; and opposingsurfaces-onthe shaft and bearing limiting movement ofthe shaft into the bearing.

2. A toolifor facing an annular surface-around-acir-- cular threaded aperture in a work piece comprising in combination a rigid tubular bearing, including a first threaded section adjacent to one end of the bearing having external dimensions-such as to fit tightly into a threaded aperture in a Work piece and a second elongatesection having external dimensions such as to'be freely insertable into the aperture; a shaft longitudinally movable in and rotatable in the bearing, said shafthavinga driving shank outside said one end of the bearing; a surface facing. member carried by the. shaft between the bearing and:

shank adjacent to andfacing'said' one end ofthe bearing; and opposing surfaces on the shaft and bearing limiting movement of the shaft into the bearing;

3. The tool of claim 2. wherein the surface facing member is a milling cutter.

References Cited in the file of this patent UNITED STATES PATENTS Jarvio Dec. 22, 1925. 

1. A TOOL FOR FACING AN ANNULAR SURFACE AROUND AN APERTURE IN A WORK PIECE COMPRISING IN COMBINATION A RIGID TUBULAR BEARING, INCLUDING A FIRST SECTION ADJACENT TO ONE END OF THE BEARING HAVING EXTERNAL DIMENSIONS SUCH AS TO FIT TIGHTLY INTO AN APERTURE IN A WORK PIECE AND A SECOND ELONGATE SECTION HAVING EXTERNAL DIMENSIONS SUCH AS TO BE FREELY INSERTABLE INTO THE APERTURE; A SHAFT LONGITUDINALLY MOVABLE IN AND ROTATABLE IN THE BEARING, SAID SHAFT HAVING A DRIVING SHANK OUTSIDE SAID ONE END OF THE BEARING; A SURFACE FACING MEMBER CARRIED BY THE SHAFT BETWEEN THE BEARING AND SHANK ADJACENT TO AND FACING SAID ONE END OF THE BEARING; AND OPPOSING SURFACES ON THE SHAFT AND BEARING LIMITING MOVEMENT OF THE SHAFT INTO THE BEARING. 